1. Field of the Invention
This invention relates to a winding device, having a winding shaft, which can be inserted into and removed from the winding device, and a winding element and bearing journals protruding from both ends in a direction of a center axis of the winding shaft, wherein the winding device has two outer bearings for receiving the bearing journals for rotatable seating of the winding shaft in the winding device, and has an additional bearing for the winding shaft spaced apart to each outer bearing.
2. Description of Prior Art
Such winding devices are known in many variations and are used, for example, for winding a continuously fed web of material, such as a plastic foil, to form a so-called coil, which is wound on the winding shaft. Customarily a tube made, for example, of cardboard, is pushed on a winding element of the winding shaft, which forms a core of the subsequent coil.
A problem with the known winding devices is flexing of the winding shaft, so far unavoidable and considerable, between its seats formed at the bearing journals in end areas. This flexing has negative effects on the winding quality obtained.
Furthermore, at the start of the winding process, for example when the fed-in material begins to be wound, the winding shaft has the smallest diameter, its own diameter or the outer diameter of a tube pushed on the winding shaft. Because of this smallest diameter, the winding shaft reaches its greatest number of revolutions here. But this maximum number of revolutions is limited by the critical bending speed of the winding shaft, which is a result of the flexing of the shaft because of its own weight. But this critical bending speed to which the winding shaft can be accelerated at the start of the winding process, limits the efficiency of the winding device, so that a further increase in the critical bending speed of the winding shaft is desirable.
A winding device is known from German Patent Reference DE 44 39 908, wherein a compensating force is exerted at the shaft ends of the winding shaft, by means of which the flexing of the winding shaft can be minimized. It is proposed for this purpose to support the winding shaft by extendible cylinders via support rollers or bearing rings, and to simultaneously introduce the desired compensation force. However, with this known device it is disadvantageous that a separate energy source is always required for the cylinders and for generating the compensating force, which also requires a control and regulating device. Therefore the structure of the known device is elaborate and expensive. The known device can only be integrated with great difficulties into a winding device wherein the winding shafts need to be replaced by automation frequently and at high speed.
A support structure is known from German Patent Reference DE 196 36 184 A1, which is rotatably seated in a sort of a bearing basket in two bearings, which are axially spaced apart. Although the flexing of the winding shaft is reduced without additional energy or control outlay, a use of automated winding devices and the possibility of simple changing of such a winding shaft is not possible.
Furthermore, various solution suggestions for seating exchangeable shafts in a device, for example winding shafts in a winding device, are known from the prior art, such as German Patent Reference DE-AS 1 009 336, U.S. Pat. No. 3,038,680, Great Britain Patent Reference GB 1 136 137 and German Patent Reference DE 75 36 100. However, it is a property of all these known to have no provision for affecting, or respectively reducing, the flexing of the winding shaft, which leads to the problems explained.
It is one object of this invention to provide a winding device of the type mentioned at the outset, wherein flexing of the winding shaft is minimized with small outlay in order to increase the critical bending speed of the winding shaft, which has advantageous results on the efficiency of the winding device and to also improve the winding quality of the winding device with the reduction of the flexing, wherein this winding shaft preferably can be inserted into and removed out of the winding device in an automated manner, i.e. it should be exchangeable.
In accordance with this invention, this object is attained with a winding device having the characteristics described in this specification and in the claims.
According to this invention, each outer bearing is equipped with a coupling device. The coupling devices are displaceable along a center axis of the winding shaft and can be connected with or disconnected from the respective ends of the bearing journals. Additional bearings between the ends of the bearing journals, which can be connected with the outer bearings and the winding element on the bearing journal of the winding shaft are designed as inner bearings.
According to this invention, for rotatable seating of the winding shaft, an outer bearing is arranged at the end of each bearing journal and a respective inner bearing is arranged, spaced apart, at the outer bearings on a side facing away from the end of the bearing journal, so that the winding shaft is quadruple seated symmetrically in the winding device. Thus, the flexing of the winding shaft seated in the winding device is reduced to a minimum. Because of the quadruple symmetrically seated winding shaft in a dual indeterminate system, tensions, and moments resulting therefrom, are caused within the winding shaft between the bearing points, which counteract the flexing of the winding shaft under its own weight, so that flexing of the winding shaft is minimized in a surprisingly simple way.
Within the scope of this invention, a symmetrical seating is understood to be an arrangement of the bearings which is symmetrical with respect to the center of the winding shaft.
To be able to remove the winding shaft from the winding device when a desired winding length of the fed-in web of material is reached, and to replace it by a further insertable winding shaft without an interruption of the feeding of the material web, the outer bearings are equipped with respective coupling devices, which are displaceable along the center axis of the winding shaft and can be connected with or disconnected from the respective ends of the bearing journals of the winding shaft. The additional bearings used as inner bearings are arranged between the ends of the bearing journals, which can be connected with the outer bearings, and the winding element on the bearing journals of the winding shaft. From there, the winding shaft is permanently equipped with its inner bearings and, when inserted into the winding device, is also connected with the respective outer bearings of the winding device by the coupling devices acting on the winding shaft. Thus, the quadruple symmetrical seating in the winding device in accordance with this invention, and minimization of the flexing of the winding shaft resulting therefrom, is achieved. When the winding shaft is to be removed again out of the winding device, the outer bearings are separated from the winding shaft by the coupling device, so that the outer bearings can be removed from the winding device in a manner known per se and exchanged for another winding shaft, which can be inserted into the winding device.
With this design it is also possible to use winding shafts with different diameters of the winding element, for example the widely used 3xe2x80x3 and 6xe2x80x3 winding shafts, in the winding device of this invention. Only the bearing journals of the winding shafts must be designed the same for this purpose.
The inner bearings of the winding shaft are each formed by a bearing sleeve pushed on the area of the bearing journal facing away from the coupling device, and are seated, rotatable around the bearing journal, using seating elements. Here, the bearing sleeve forms the outermost bearing housing of the inner bearing, while the bearing journal forms the inner housing of the inner bearing. It is also possible to push at least one inner sleeve, which simultaneously forms the inner housing of the inner bearing, on the bearing journal, through which the bearing elements are rotatably connected with the bearing sleeve pushed over it as an outer bearing housing. In this case the inner bearings of the winding shaft are advantageously embodied as rolling bearings, which can also dependably absorb the loads created by the weight of the winding shaft, together with the web of material being wound onto this winding shaft.
A receiver cup, approximately U-shaped in cross section, is provided for supporting the inner bearing of the winding shaft within the winding device, into which the winding shaft can be inserted for rotatable seating in the winding device, and from which it can be removed. The automatic insertion and removal of winding shafts into, or respectively out of, the winding device in accordance with this invention is thus made possible.
A particularly solid seating of the winding shaft is achieved because the receiver cup is extended past the coupling device for the outer bearing and forms a part of the bearing bracket for the outer bearing.
In an advantageous further embodiment of this invention, the bearing sleeve of the inner bearing has an annular circumferential groove on the outside. The receiver cup has a strip, which corresponds with it and which, with the winding shaft inserted into the receiver cup, interlockingly engages the circumferential groove of the bearing sleeve. Axial displacement of the bearing sleeve of the inner bearing of the winding shaft during the winding process is thus prevented.
For a further increase of the fixation and support of the inner bearings of the winding shaft on the winding device, the strips forming the U-shaped cross section of the receiver cup have a distance from each other, which corresponds to the diameter of the bearing sleeve of the inner bearing. Thus the bearing sleeve can be interlockingly placed into the receiver cup and can be inserted, or respectively removed, without problems through the remaining free space between the strips forming the U-shaped cross section of the receiver cup.
In order to be able to insert the winding shafts of the winding device of this invention without problems into the latter, or respectively to take them out again, a cylinder is held in the winding device, is axially displaceable in relation to the center axis of the winding shaft, forms the coupling device for the outer bearings. A center sleeve is seated, rotatable by the outer bearing, and the center sleeve engages the free end of the bearing journal during a displacement of the cylinder in a direction toward the winding shaft and seats the winding shaft rotatably in the outer bearing. This engagement can be released again by displacing the cylinder in the opposite direction, and the winding shaft can be released.
To insert the winding shaft into the winding device in accordance with this invention, the winding shaft is inserted with bearing journals into the respectively provided receiver cups of the winding device. The inner bearings formed on the bearing journal of the winding shaft are supported on the winding device and cause a double rotatable seating of the winding shaft. A connection between the free end of the bearing journal of the winding shaft and the outer bearing, which rotatably seats the center shaft, is then accomplished in this position by displacing the cylinder with the center shaft rotatably seated therein in the direction toward the center axis of the winding shaft. Now the quadruple symmetrical seating in accordance with this invention, of the winding shaft results, which minimizes flexing of the winding shaft. Following the end of the winding process on the winding shaft seated in this way in the winding device, the cylinder is displaced in the opposite direction, whereupon the center shaft disengages with the bearing journal of the winding shaft and the connection with the outer bearings is broken. It is now possible to take the winding shaft out of the receiver cups of the winding device in the reverse direction.
With the above explained structural design it is possible to perform an automated changing of the winding shafts in the winding device. It is thus, for example, merely necessary to fasten the coupling device and the receiver cups on changing arms, known per se, of a winding device in the area of the free end thereof, so that the winding shaft can be inserted with a pivot movement of the changing arms into a receiving position, and the winding shaft can be taken out of the receiver cups by means of a further pivot movement of the changing arms into a removal position.
The subsequent equipping of already present winding devices with the quadruple symmetrical seating proposed by this invention, for minimizing the flexing of the winding shaft, is in particular possible by means of this simple construction.
In an advantageous further embodiment of the winding device in accordance with this invention, on its free end the center shaft has a clamping cone, which can be brought into engagement with a corresponding conical clamping bore axially cut into a free end of the bearing journal. Thus a particularly solid connection is possible between the outer bearings and the bearing journals of the winding shaft for providing the quadruple symmetrical seating in accordance with this invention.
With very productive winding devices of this invention, which have great winding widths in particular, the center shaft can be rotatably driven by a rotary drive in order to transmit rotating movement to the winding shaft upon engagement of the center shaft with the bearing journal of the winding shaft, and thus to rotatably drive the winding shaft during the winding operation.
A coupling sleeve can be placed on the area facing the free end of the bearing journal, which is connected, fixed against relative rotation, with the bearing journal by means of a shaft-hub connection, and on whose free end the clamping bore is provided. It is possible by means of this design to equip already existing winding shafts of different diameters without a large outlay with an inner bearing using the bearing sleeve pushed thereon, as well as with a conical clamping bore provided for the engagement of the coupling device on the free end of the bearing journal by means of the coupling sleeve.
A pneumatic valve can be provided inside the coupling sleeve for a compressed air connection to the winding shaft, such as is known, for example, for actuating clamping cheeks, which can be extended out of the surface of the winding element of the winding shaft for fixing a tube in place, which is pushed thereon for winding of the fed web of material thereon.
Also, the bearing sleeve which is rotatably arranged on the bearing journal for creating the inner bearing, can be rotatably seated with respect to the bearing journal using an additional roller bearing in the area of its end facing the coupling sleeve in order to prevent an interference with the coupling sleeve adjoining there, which is connected, fixed against relative rotation, with the bearing sleeve.
The reduction of the flexing of the winding shaft which can be achieved with the quadruple symmetrical bearing, in accordance with this invention, of the winding shaft can be realized in connection with the most varied constructions of winding devices. It can be advantageously employed with so-called contact winders, wherein a direct contact between a so-called contact roller and the winding shaft exists, and also with so-called gap winders, wherein the contact roller and the winding shaft have a defined gap distance from each other, which can be preset, in order to minimize the flexing of the winding shaft and to improve the winding result as well as the winding device output.